8.1 Which gases are analysed with a gas analyser?
8.2 State THREE manufacturer's specifications that must be obtained for a specific engine when conducting a gas analysing test - NSC Mechanical Technology Automotive - Question 8 - 2018 - Paper 1
Question 8
8.1 Which gases are analysed with a gas analyser?
8.2 State THREE manufacturer's specifications that must be obtained for a specific engine when conducting a gas a... show full transcript
Worked Solution & Example Answer:8.1 Which gases are analysed with a gas analyser?
8.2 State THREE manufacturer's specifications that must be obtained for a specific engine when conducting a gas analysing test - NSC Mechanical Technology Automotive - Question 8 - 2018 - Paper 1
Step 1
Which gases are analysed with a gas analyser?
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Answer
The gases typically analysed with a gas analyser include:
Exhaust gasses
Carbon monoxide (CO)
Carbon dioxide (CO₂)
Sulfur dioxide (SO₂)
Nitrogen oxides (NOx)
Hydrocarbons (HC)
Oxygen (O₂)
Step 2
State THREE manufacturer's specifications that must be obtained for a specific engine when conducting a gas analysing test.
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Answer
The manufacturer's specifications that must be obtained include:
Percentages of Hydrocarbons (HC)
Carbon monoxide (CO) content
Carbon dioxide (CO₂) content
Step 3
State TWO possible results observed when a cylinder leakage test is conducted on an internal combustion engine.
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Answer
Possible results observed from a cylinder leakage test include:
Hissing noise at the air intake
Hissing noise at the exhaust pipe
Step 4
State TWO causes of cylinder leakages that can be determined when conducting a cylinder leakage test on an internal combustion engine.
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Answer
Causes of cylinder leakages include:
Worn piston rings
Cracked cylinder head or block
Step 5
Explain the procedures to be followed when conducting a compression test on an internal combustion engine.
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Answer
The procedures to follow when conducting a compression test are:
Get the engine to normal operating temperature.
Disconnect the fuel supply and ignition system.
Remove the spark plugs.
Fit the compression tester.
Depress the throttle and crank the engine a few revolutions.
Record and compare the pressure reading for each cylinder with manufacturer specifications.
Step 6
Give TWO reasons for low oil pressure in an internal combustion engine.
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Answer
Reasons for low oil pressure can include:
Worn oil pump
Blocked oil pump screen/filter/strainer in the sump
Step 7
Explain in point form how you conduct a cooling system pressure test.
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To conduct a cooling system pressure test:
Start the engine and allow it to heat up.
Fit the radiator pressure tester to the radiator.
Pressurize the cooling system according to manufacturer’s specifications.
Monitor the pressure for a while; if it drops, there is a leak.
Make a visual check for leaks.
Install radiator cap and observe gauge; the gauge should release pressure.
